Device for unwinding a web of material from a supply roll

ABSTRACT

Apparatus for unwinding an intermittently fed web from a web supply roll mounted by rapid action clamping means in a stand comprises guide means in the stand for guiding the web off the supply roll. Said guide means comprise at least three guide members about which the unwound web is passed, one of the guide members being displaceable towards and away from the other guide members to form a reserve loop of web material. During web feed, the length required is taken from the reserve loop, thereby causing the displaceable guide member to approach the other guide members. During standstill periods between successive web feeds, the reserve loop is replenished from the supply roll by forcing the displaceable guide member further away again and thereby causing the supply roll to turn, brake means being provided to halt the supply roll when the displaceable guide member has moved away to a predetermined extent.

[ Oct. 14, 1975 United States Patent 1191 Bauer DEVICE FOR UNWINDING A WEB OF m t mm hJ a r 6 mam m 3% 1H m We m 1 nm W PA L L O RmM wa a mm m Sw G A m Mm? O ww mu vma &EFP

V mm [22] Filed Apr 30 1974 Apparatus for unwinding an intermittently fed web from a web supply roll mounted by rapid action clamping means in a stand comprises guide means in 21 Appl. No.: 465,726

the stand for guiding the web off the supply r011. Said guide means comprise at least three guide members [30] M S 2 Apphcatlon Pnonty Data about which the unwound web is passed, one of the guide members being displaceable towards and away fr Germanym......................... 2323430 om the other guide members to forma reserve loop [52] US. 242/7543, 139/109 of web material During web feed, the length required Int. Cl. B65H 25/22 is taken from the reserve loopithereby causing the displaceable guide member to approach the other [58] Field of Search 242/7543, 75.3, 75, 68.4;

guide members. During standstill periods between successive web feeds, the reserve loop is replenished from [56] References Clted the supply roll by forcing the displaceable guide mem- :UNITED STATES PATENTS ber further away again and thereby causing the supply roll to turn, brake means being provided to halt the supply roll when the displaceable guide member has moved away to a predetermined extent.

3 mm i .2 .4 2

242/7543 Ottavan 17 Claims, 3 Drawing Figures US. Patent 0a. 14, 1975 Sheet 1 of 3 3,912,189

us. Patent 0ct.14,1975 sheetzofs 3,912,189

US. Patent Oct. 14, 1975 Sheet 3 of3 3,912,189

DEVICE FOR UNWINDING A WEB OF MATERIAL FROM A SUPPLY ROLL The invention relates to a winding device for unwinding an intermittently pulled-off web of material from a supply roll, with a winding stand and with, disposed in the stand, mandrels for supporting the supply roll.

Modern processing machines, for example packing machines for packeting objects in shrunk-on film, have particular winding means for unwinding the web of material from a supply roll during operation. Particular demands have to be made on the winding apparatus if pieces of film corresponding to the length required for processing in each case are intermittently drawn from the supply roll held in this apparatus. For on the one hand the web of film pulled off and passed around direction-changing rollers must always be under adequate tension in order to prevent abrupt loadings during sudden pulling movements, and on the other, the supply roll is of considerable weight and therefore has a high moment of inertia so that during stepwise pulling of the web of film, considerable acceleration and deceleration forces result if it is intended that the web of film being pulled off is always subject to adequate and as far as possible even tension.

The object of the invention, therefore, is to provide an unwinding means which permits of maintenance of adequate tension in the intermittently pulled-off web of film which can be easily operated.

According to the invention, this problem is resolved in that for guiding the web of film, at least three guide rollers or rails are provided which are disposed transverse] y to the direction of film movement, two of them being mounted in the winding stand and one, about which the web of film is guided in order to form a supply loop, is disposed in an extensible holder for movement parallel with itself, and in that the movable roller or rail can be moved from its inner position with the smallest loop into its extended position by the force of a spring, a pneumatic piston-cylinder unit, a linear motor or the like, and in that the mandrels for supporting the roller are freely rotatable and are constructed to be clamped by a separable clamping means against the supply roll, one of the mandrels being provided with a brake which takes effect when the roller forming the loop is extended, and in that a locking means is provided to prevent the web of film pulled off from running back. The apparatus according to the invention ensures that despite the considerable moment of inertia of the supply roll, the web of film can be intermittently pulled off the supply roll with adequate substantially constant web tension. When the processing machine downstream of the unwinding device pulls off a piece of film web of definite length with high acceleration, then the movably or oscillatingly disposed extensible roller is moved by half the pulled-off length of film web towards the adjacent direction-changing rollers, the supply loop becoming correspondingly smaller. The pulled-off piece of film web is taken from the supply loop without the supply roll having to be caused to rotate thereby. During pull-off, only one directionchanging roller is caused to rotate and the oscillating roller forming the loop is moved together with its support, and these have only minimal inertia so that the acceleration forces occurring are only small and can be absorbed by the web of film without fear of the film being damaged. Where reversing rails are used instead of direction-changing rollers, there is only negligibly small friction between them and the surface of the film. The drive which moves the extensible roller or direction-changing rail into the extended position is so constructed that it has no notable reaction on the pull-in movement. By reason of the fact that a non-return lock is provided at the outlet from the winding apparatus or at the input of the processing machine to prevent the web of film rolling back after it has been pulled off, the oscillating roller which is moved back into its extended position by a drive which may be provided by spring force, a compressed air cylinder or by some other means, pulls that piece of film web which is stored in the supply loop from the supply roll which is mounted for free rotation in the mandrels. The drive is thereby so selected that forces acting continuously on the oscillating roller cause the supply roll to rotate only slowly, so that the acceleration forces to drive the supply roll are only minimal. When the extreme position of the oscillating roller is reached, the brake acting on a winding mandrel arbor operates and immobilises the supply roll so that a minimum tension is retained in the web of film. Since the supply roll is caused to rotate only slowly by the pull-off means, the brake only has a minimal kinetic energy of rotation to dissipate. It is advantageous for the oscillating roller to be moved into its extended position by a spring which is tensed during film pull-off because the tensed spring then, on commencement of pull-off of film web from the supply roll, applies the greatest force, this force then diminishing once the supply roll has started to rotate so that only a correspondingly diminished braking effect is required.

The non-return lock for the pulled-off web of film may consist of a series of upwardly pivotable clamping blocks which rest on the web of film.

The movable roller or direction-changing rail is expediently constructed as an oscillating roller or rail disposed between two pivotable arms. The pivotable arms may carry a lever which is preferably adjustably disposed on their pivoting axis and which actuates the supply roll brake when or shortly before the extended position of the oscillating roller or rail is reached. The brake may take the form of a band or shoe brake.

The partial problem of easy operation of the winding apparatus is resolved by the rapid clamping device according to the invention, which consists of a carrier displaceable on a guide and carrying a freely rotatable mandrel which can be moved in the direction of the supply roll axis through a lever and linkage, a locking means being provided in the clamping direction to secure the depressed position and trigger the forwards movement in the direction of release. After the core of the used-up supply roll has been detached and removed, it is necessary only for the new supply roll with its central winding aperture or its winding sleeve to be lifted into the region of the lockable mandrels, whereupon the rapid locking device is actuated and the roll brought into the position of use. The locking mandrels are expediently of conical construction so that the supply roll centres itself on them. The rapid locking device may be operated via a hand lever or preferably via pedals.

In a further development of the invention, for adjusting the locking mandrels of the width of the film supply roll, a left-hand and a right-hand thread spindle are provided, the spindle nuts of which are in each case connected to one of the locking mandrel supports, the left-hand and right-hand threaded parts of the spindles being connected by ain the direction of rotationform-locking telescopic connection and the locking and releasing movement being transmitted from a lever to a ring which is rotatably but axially immovably mounted on the spindle shaft. The locking and releasing forces can be initiated and transmitted in this way via the spindles. The telescopic connection which expediently consists of a square-end plug-in connection, serves to receive the rapid locking movements in that it allows a spindle part to be disengaged or to be applied under pressure.

The forces for axial movement of the spindle part which performs the locking movement are expediently transmitted through angle levers and linkage.

In the case of the locking movement, ajointly moved locking pawl may be provided to engage in ratchet teeth which are rigid with the machine, the opening movement becoming locked thereby. Upon actuation of the release lever or pedal, the locking pawl is detached during the first part of the lever movement, whereupon the opening movement is transmitted to the locking mandrel support.

The carriers which support the rotatable mandrels are expediently guided on two cross members in the stand and are adapted for longitudinal displacement.

According to the invention, optimum utilisation of the winding apparatus is achieved in that a plurality of supply roll unwinding means are disposed in a stand. If the unwinding apparatus is designed for example for the unwinding of two supply rolls at the same time, the facing sides of the rolls are adjusted to the necessary minimum gap and the two outer carriers are aligned to whichever is the width of the film. If, then, the winding apparatus is changed-over from twin drive to single drive, then the carriers of the mandrels are aligned so that the transverse axis of the roll lies in the centre. In

order to ensure a simple displacement of the carriers for the locking mandrels on the guide cross-members, these latter must be released from the associated spindle nuts. For this purpose, according to the invention, coupling pieces are provided by which the carriers can be detached from the spindle nuts. Suitable coupling pieces are for example shoes with bayonet-type elongated holes which lock together pin members disposed both on the carrier as well as on the spindle nuts.

The spindle drive serves for adjustment to the width of supply roll. Once this width has been adjusted, the supply roll can be changed solely by operating the rapid locking means.

According to the invention, satisfactory operation of the winding apparatus is furthermore guaranteed by the provision of a ramp which can be raised through a system oflevers. The ramp according to the invention ideally has a part inclined obliquely to the bottom, and adjacent to which there is a supporting trough. For fitting a new roll which is frequently of considerable weight, the roll is rolled up the oblique surface until it comes to rest in the supporting trough. Via a linkage operated by a hand lever, preferably a parallel linkage, the roller spindle can be lifted easily into the region of the winding mandrels, so that the new roll can easily be brought into a position of readiness for use by actuation of the rapid locking means. By reason of the device according to the invention, a roll can be comfortably changed by one operator.

For welding the beginning of the new roll to the trailing end of the used roll, a further development of the invention provides a welding die which can be pivoted into the film web and against which a hand-guided matching die can be pressed. When pressure is exerted, the welding die actuates a switch which provides the current pulse required for welding. In order to secure the webs of film which have to be connected to each other, a row of needles onto which the web of film can be threaded by a brush strip, is provided above the welding die. A sensor arm can rest on the supply roll to switch off the processing machine as soon as the supply roll has been used to the extent that only a small remnant remains.

An example of embodiment of the invention is explained in greater detail hereinafter with reference to the attached drawings, in which:

FIG. 1 is a perspective view of the unwinding apparatus;

FIG. 2 is a perspective view of a part of the rapid locking device, and

FIG. 3 shows the welding device.

The winding stand 1 consists of side walls 2, 3 which are connected to each other by the cross-members 4, 5, 6. Guided for longitudinal displacement on the crossmembers 4, 5 are triangularly shaped carriers 8, 9 for the freely rotatable supporting mandrels 10, 11. The supply roll 12 indicated by dashdotted lines is supported on the mandrels 10, 11. From the supply roll 12, the web of film 13 likewise shown in dash-dotted lines, is guided over the guide rollers 36, 35 to the oscillating roller 17 and back to the guide roller 34, a loop being formed. From the guide roller, the web of film 13 runs to the processing machine at the input of which there is the (not shown) non-return lock to control the web of film 13. The oscillating roller 17 is mounted on the spindle 16 in the mutually parallel links 14, 15 which are adapted to pivot about the cross-member 5. At their ends which project beyond the cross-member 5, the links 14, 15 are connected to each other by a carrier 18, so that a rugged frame is formed. Also rotatably mounted on the cross-member is the lever 19, that end thereof which projects beyond the cross-member 5 being secured on the carrier 18. At its free end, the lever 19 is articulatingly connected to the bar 20 which is articulated at its other end to the lever 21 for actuating the brake shoe 22 and which can be pivoted about the spindle 24 of the supporting piece which is a continuation of the carrier 9. The locking mandrel shaft mounted in the carrier piece 9 is, at its end which protrudes from the carrier piece, connected to the disc 23 against which the brake shoe 22 can be pressed.

The ramp 29 which is inclined obliquely towards the ground and up which the supply rolls 12 can be rolled, is provided with a supporting trough 43 while on its back it has bifurcated supports 32. Articulated at hing ing points 40 and 41 on these bifurcated supports are a shorter lever 31 and a longer lever 30. The shorter lever is rotatably mounted on the cross-member 6 while the longer lever is rigidly connected to the shaft 7 mounted in the side walls 2, 3 and rotatable via the hand lever 33.

Also rotatably mounted on the cross-member 6 is the lever 25 which operates the rapid locking means. The lever 25 consists of the two mutually parallel plates 60, 61 which are provided with bushings 73. Rigidly connected to the lever 25 is the pedal 26 which transmits the locking movement. Furthermore, the rail 28 which operates the angle lever 49, 50 for axial displacement of the spindle part 44, is articulatingly connected to the lever 25. r f

Connected to the links l4, l5 and secured on the machine frame is a spring 42, thespring force of which acts on the parallel links, tending to pivot them outwardly. The pivoting angle of the parallel links 14, is fixed by adjustable stops.

The rapid locking means is explained in greater detail with reference to FIG. 2. The locking pedal 26 is connected to the two plates 60, 61 which form the lever and forms with this lever an angle lever which can pivot about the cross-member 6. Articulatingly mounted be tween the plates 60, 61, at the point 62, is the push and pull rod 28 which at its opposite end is articulatingly connected to'the angle lever formed by the arms 49, 50, the connection being made at the arm 50 thereof. The angle lever 49, 50 is pivotable about the shaft 52 mounted in the block 51. The block 51 is mounted on the side wall 2 of the stand. The lever arm 49 is of bifurcated construction and carries at its free end elongated holes 49 engaged by pin members disposed on the ring 46. The ring 46 which is rotatably but axially immovably mounted on the spindle shaft 44, is held by bifurcating means on the lever arms 49. When the locking pedal 26 is operated, the push/pull rod 28 is moved via the angle lever 25 while the right-hand part 44 of the spindle is moved via the angle lever 49, 50 to produce the locking action. When this happens, the pawl 58 engages into the teeth of the ratchet 59 and secures the forwardly pushed position. The pawl 58 is mounted on the supporting piece 56 which is mounted between the plates 60, 61 for rotation about the spindle 55, the supporting piece 56 having a projection 57 which serves to release the lock. The release pedal 27 is mounted between the plates 60, 61 to pivot around the spindle 53 and is connected to the lever 54 which releases the locking system. When the release pedal 27 is operated, the locking pawl 58 is first lifted out of its locking position, after which the angle lever 25 is pivoted in the opposite direction so that the rod 28 is subjected to a tractive loading and releases the locking means via the angle levers 49, 50.

The parts 72, 44 of the spindle which can be operated by the hand wheel 63, have oppositely directed pitches. The spindle parts are connected to each other by the telescopic plug-in connection 45 so as to be axially displaceable and to be form-lockingly connected in the direction of rotation. Disposed on the spindle parts 72, 44 are spindle nuts via which the supporting pieces 8, 9 can be displaced on their guides 4, 5. So that the supporting pieces can be displaced on their guides for example upon change-over from single operation to twin operation, the spindle nuts are connected to the supporting pieces through separable couplings.

The welding arrangement for joining the end of the roll to the beginning of the new roll will be explained in greater detail with reference to FIG. 3. The welding arrangement 37 can be pivoted by the lever 39 about the axis 38 into the path of the film 13 passing over the rollers 36, 35. The welding means consists of the welding die 74 with the resistance Welding wire 70 placed on it. When pressure is applied from the front, the welding die 74 can be pressed against a switch 66 which triggers a welding current pulse. The counter die 64 consists of a hand-operated strip with a handle .,71

provided.

which carries on its front edge a Teflon support 65. Disposed parallel with the welding die 74 is a row of needles '67 onto which the beginning of the new supply roll 68 and the end of the expiring supply roll 69 can be threaded in order to be secured to each other. To facilitate'threading, a hand-operated bristle-carrying strip is I claim:

1. Apparatus for unwinding an intermittently fed web of material from a supply roll comprising: a stand; freely rotatable stub mandrels mounted in said stand for supporting a supply roll; a displaceable support mounted on said stand;guide means in said stand for guiding a web off said supply roll, thus forming an unwound web; said guide means comprising at least three elongated guide members about which the unwound web can be passed and which extend substantially parallel to the rotary axes of said stub mandrels, two of said guide members being mounted at fixed locations in said stand and a third of said guide members being mounted on said displaceable support for movement within limits towards and away from said two guide members whereby to shorten and lengthen. respectively, a loop of the unwound web extending between said third guide member and said two guide members; means for urging said third guide member away from said two guide members; clamping means for releasably holding said stub mandrels to said supply roll; brake means operatively connected to one of said stub mandrels; and means effective to apply said brake means when said third guide member is at its said limit of movement away from said two guide members.

2. Apparatus according to claim 1, wherein said third guide member comprises a roller and the displaceable support thereof comprises two supporting arms mounted for limited pivotal movement on said stand.

3. Apparatus according to claim 2, including a pivot shaft upon which said supporting arms are commonly mounted and wherein said brake applying means comprise a lever which is fixed on said pivot shaft and is operatively connected to said brake means.

4. Apparatus according to claim 1, wherein said brake means comprise a brake shoe cooperating with a brake disc connected to one of said stub mandrels.

5. Apparatus according to claim 1, wherein said means for urging said third guide member comprise a spring extending between said stand and one of said supporting arms.

6. Apparatus according to claim 1, further including a mounting arm associated with and carrying each of said freely rotatably stub mandrels, and wherein said clamping means comprise one of said mounting arms, said one mounting arm being supported in said stand for displacement in the axial direction of said mandrels, an operating mechanism effective to displace said one mounting arm, and locking means for locking said one mounting arm in a displaced position at which said supply roll is held by said stub mandrels.

7. Apparatus according to claim 6, including means for adjusting said stub mandrels to a particular width of said supply roll, wherein said adjusting means comprise a two-part spindle provided with a left-hand screwthread on one part and a right-hand screwthread on the other part, a nut on each of said supporting arms engaging a respective one of said spindle parts, and telescopic coupling means connecting said spindle parts in coaxial relationship for corotation and for relative displacement in the axial direction of said spindle, and wherein said operating mechanism of said clamping means include a ring mounted for rotation on one of said spindle parts but fixed against axial displacement.

8. Apparatus according to claim 7, wherein said operating mechanism includes levers connecting said ring to foot pedals.

9. Apparatus according to claim 6, wherein said locking means comprise a pawl and ratchet device.

10. Apparatus according to claim 8, wherein said locking means comprise a pawl and ratchet device and one of said foot pedals is adapted to disengage said pawl from said ratchet before displacing said one mounting arm.

11. Apparatus according to claim 1, including means for supporting a plurality of said supply rolls in said stand.

12. Apparatus according to claim 1, including a coupling element effective to release each said nuts from said supporting arm.

13. Apparatus according to claim 1 including a ramp and means for raising and lowering said ramp.

14. Apparatus according to claim 13, wherein said ramp comprises an inclined lower portion directed downwardly and an upper portion provided with a supporting trough.

15. Apparatus according to claim 1, including a first welding jaw, means for projecting said first welding jaw into the path of said unwound web, a second welding jaw, and manually operable means for applying said second jaw to said first jaw.

16. Apparatus according to claim 15, wherein said first welding jaw is displaceable in response to application of said second jaw and further including an electric switch for actuation by said first jaw in its displaced position.

17. Apparatus according to claim 15, including a row of needles parallel to said first welding jaw. 

1. Apparatus for unwinding an intermittently fed web of material from a supply roll comprising: a stand; freely rotatable stub mandrels mounted in said stand for supporting a supply roll; a displaceable support mounted on said stand; guide means in said stand for guiding a web off said supply roll, thus forming an unwound web; said guide means comprising at least three elongated guide members about which the unwound web can be passed and which extend substantially parallel to the rotary axes of said stub mandrels, two of said guide members being mounted at fixed locations in said stand and a third of said guide members being mounted on said displaceable support for movement within limits towards and away from said two guide members whereby to shorten and lengthen, respectively, a loop of the unwound web extending between said third guide member and said two guide members; means for urging said third guide member away from said two guide members; clamping means for releasably holding said stub mandrels to said supply roll; brake means operatively connected to one of said stub mandrels; and means effective to apply said brake means when said third guide member is at its said limit of movement away from said two guide members.
 2. Apparatus according to claim 1, wherein said third guide member comprises a roller and the displaceable support thereof comprises two supporting arms mounted for limited pivotal movement on said stand.
 3. Apparatus according to claim 2, including a pivot shaft upon which said supporting arms are commonly mounted and wherein said brake applying means comprise a lever which is fixed on said pivot shaft and is operatively connected to said brake means.
 4. Apparatus according to claim 1, wherein said brake means comprise a brake shoe cooperating with a brake disc connected to one of said stub mandrels.
 5. Apparatus according to claim 1, wherein said means for urging said third guide member comprise a spring extending between said stand and one of said supporting arms.
 6. Apparatus according to claim 1, further including a mounting arm associated with and carrying each of said freely rotatably stub mandrels, and wherein said clamping means comprise one of said mounting arms, said one mounting arm being supported in said stand for displacement in the axial direction of said mandrels, an operating mechanism effective to displace said one mounting arm, and locking means for locking said one mounting arm in a displaced position at which said supply roll is held by said stub mandrels.
 7. Apparatus according to claim 6, including means for adjusting said stub mandrels to a particular width of said supply roll, wherein said adjusting means comprise a two-part spindle provided with a left-hand screwthread on one part and a right-hand screwthread on the other part, a nut on each of said supporting arms engaging a respective one of said spindle parts, and telescopic coupling means connecting said spindle parts in coaxial relationship for corotation and for relative displacement in the axial direction of said spindle, and wherein said operating mechanism of said clamping means include a ring mounted for rotation on one of said spindle parts but fixed against axial displacement.
 8. Apparatus according to claim 7, wherein said operating mechanism includes levers connecting said ring to foot pedals.
 9. Apparatus according to claim 6, wherein said locking means comprise a pawl and ratchet device.
 10. Apparatus according to claim 8, wherein said locking means comprise a pawl and ratchet device and one of said foot pedals is adapted to disengage said pawl from said ratchet before displacing said one mounting arm.
 11. Apparatus according to claim 1, including means for supporting a plurality of said supply rolls in said stand.
 12. Apparatus according to claim 1, including a coupling element effective to release each said nuts from said supporting arm.
 13. Apparatus according to claim 1 including a ramp and means for raising and lowering said ramp.
 14. Apparatus according to claim 13, wherein said ramp comprises an inclined lower portion directed downwardly and an upper portion provided with a supporting trough.
 15. Apparatus according to claim 1, including a first welding jaw, means for projecting said first welding jaw into the path of said unwound web, a second welding jaw, and manually operable means for applying said second jaw to said first jaw.
 16. Apparatus according to claim 15, wherein said first welding jaw is displaceable in response to application of said second jaw and further including an electric switch for actuation by said first jaw in its displaced position.
 17. Apparatus according to claim 15, incluDing a row of needles parallel to said first welding jaw. 